MireaBackend/Endpoint/Configuration/AppConfig/EnvironmentConfiguration.cs

using Microsoft.Extensions.Configuration;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Mirea.Api.Endpoint.Configuration.AppConfig;

public static class EnvironmentConfiguration
{
    private static IDictionary<string, string> LoadEnvironment(string envFile)
    {
        Dictionary<string, string> environment = new();

        if (!File.Exists(envFile)) return environment;

        foreach (var line in File.ReadAllLines(envFile))
        {
            if (string.IsNullOrEmpty(line)) continue;

            var commentIndex = line.IndexOf('#', StringComparison.Ordinal);

            string arg = line;

            if (commentIndex != -1)
                arg = arg.Remove(commentIndex, arg.Length - commentIndex);

            var parts = arg.Split(
                '=',
                StringSplitOptions.RemoveEmptyEntries);

            if (parts.Length > 2)
                parts = [parts[0], string.Join("=", parts[1..])];

            if (parts.Length != 2)
                continue;

            environment.Add(parts[0].Trim(), parts[1].Trim());
        }

        return environment;
    }

    public static IConfigurationRoot GetEnvironment()
    {
        var variablesFromFile = LoadEnvironment(".env");

        var environmentVariables = Environment.GetEnvironmentVariables()
            .OfType<DictionaryEntry>()
            .ToDictionary(
                entry => entry.Key.ToString() ?? string.Empty,
                entry => entry.Value?.ToString() ?? string.Empty
            );

        var result = new ConfigurationBuilder()
            .AddInMemoryCollection(environmentVariables!)
            .AddInMemoryCollection(variablesFromFile!);

#if DEBUG
        result.AddInMemoryCollection(LoadEnvironment(".env.develop")!);
#endif

        Environment.SetEnvironmentVariable("PATH_TO_SAVE", variablesFromFile["PATH_TO_SAVE"]);

        return result.Build();
    }
}